Carburetors operate by controlling the movements to an adjustable plate called the throttle plate, which 'opens up' to allow more fuel and thus more power into the intake valve.
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* A carburetor can mix too little fuel with air - this is called a "lean" mixture. A carburetor can mix too much fuel, which is a "rich" mixture that provides a lot of power.
* A larger carburetor will allow the engine to draw in more air, if it is too big it is almost as bad as a carburetor that is too small.
** On a fuel-injected car, a throttle body that is too big will put too much gas in the combustion chamber that flows out in the exhaust unburnt.
** It is much more of a problem on a carbureted car, which will make the engine perform terribly at part throttle.
** A simple formula for calculating the proper carburetor setup is:
CFM (amount of air the engine needs) = Displacement (in cubic inches) X Maximum RPM / 3,456
Although carburetors stop being used in cars in 1990, carburetors are still used in smaller motors like motorcycles, lawnmowers, and chain saws.
